US2024396033A1PendingUtilityA1
Cathode active material for lithium secondary battery and lithium secondary battery including the same
Est. expiryMay 23, 2043(~16.8 yrs left)· nominal 20-yr term from priority
H01M 2004/028H01M 10/052H01M 4/525Y02E60/10H01M 2004/021H01M 4/505C01G 53/82C01P 2002/60C01G 53/50C01G 53/42
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Claims
Abstract
A cathode active material for a lithium secondary battery includes a lithium-transition metal oxide particle. A crystal index (CI) of the lithium-transition metal oxide particle is 15 or more. A lithium secondary includes a cathode including the cathode active material, and an anode facing the cathode. The cathode active material and the lithium secondary battery have improved operational reliability and thermal stability.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A cathode active material for a lithium secondary battery comprising a lithium-transition metal oxide particle that has a crystal index (CI) defined by Equation 1 of 15 or more:
CI
=
L
(
0
0
3
)
×
L
(
1
1
0
)
η
×
1
0
0
0
0
[
Equation
1
]
wherein, in Equation 1, CI is the crystal index, L(003) is a crystallite size (nm) in a (003) plane direction of the lithium-transition metal oxide particle measured through an X-ray diffraction (XRD) analysis, L(110) is a crystallite size (nm) in a (110) plane direction of the lithium-transition metal oxide particle measured through the XRD analysis, and η is a lattice strain (dimensionless number) calculated by applying a Williamson-Hall method defined by Equation 2 to peaks of the lithium-transition metal oxide particle obtained from the XRD analysis,
β
cos
θ
=
η
sin
θ
+
λ
/
D
[
Equation
2
]
wherein, in Equation 2, B is a full width at half maximum (rad) of a peak of the lithium-transition metal oxide particle obtained by the XRD analysis, θ is a diffraction angle (rad), and n is the lattice strain (dimensionless number), λ represents an X-ray wavelength (Å), and D represents a crystallite size (Å).
2 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lattice strain of the lithium-transition metal oxide particle is a slope of a straight line calculated by obtaining full widths at half maximum of all peaks in the XRD analysis, substituting the obtained full widths at half maximum into Equation 2, and plotting with sinθ as a horizontal axis and βcosθ as a vertical axis.
3 . The cathode active material for a lithium secondary battery of claim 1 , wherein L(003) of Equation 1 is measured by Equation 3 below:
L
(
0
0
3
)
=
0
.
9
λ
βcosθ
[
Equation
3
]
wherein, in Equation 3 above, L(003) represents the crystallite size (nm) in the (003) plane direction of the lithium-transition metal oxide particle, λ represents an X-ray wavelength (nm), β represents a full width at half maximum (FWHM) (rad) of a peak corresponding to the (003) plane of the lithium-transition metal oxide particle, and θ represents a diffraction angle (rad).
4 . The cathode active material for a lithium secondary battery of claim 1 , wherein L(110) in Equation 1 is measured by Equation 4 below:
L
(
1
1
0
)
=
0
.
9
λ
β
cos
θ
[
Equation
4
]
wherein, in Equation 4 above, L(110) represents the crystallite size (nm) in the (110) plane direction of the lithium-transition metal oxide particle, λ represents an X-ray wavelength (nm), β represents a full width at half maximum (FWHM) (rad) of a peak corresponding to the (110) plane of the lithium-transition metal oxide particle, and θ represents a diffraction angle (rad).
5 . The cathode active material for a lithium secondary battery of claim 1 , wherein the crystal index is in a range from 15 to 120.
6 . The cathode active material for a lithium secondary battery of claim 1 , wherein L(003) in Equation 1 is 300 nm or more.
7 . The cathode active material for a lithium secondary battery of claim 1 , wherein L(003) in Equation 1 is in a range from 320 nm to 420 nm.
8 . The cathode active material for a lithium secondary battery of claim 1 , wherein L(110) in Equation 1 is in a range from 120 nm to 300 nm.
9 . The cathode active material for a lithium secondary battery of claim 1 , wherein n in Equation 1 is 0.18 or less.
10 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lithium-transition metal oxide particle includes a polycrystalline structure in a crystallographic aspect.
11 . The cathode active material for a lithium secondary battery of claim 1 , wherein the lithium-transition metal oxide particle has a composition represented by Chemical Formula 1-1:
[Chemical Formula 1-1] Li x Ni a M1 b1 M2 b2 O 2+z wherein, in Chemical Formula 1-1, 0.9≤x≤1.2, 0.5≤a≤0.99, 0.01≤b1+b2≤0.5, −0.5≤z≤0.1, M1 includes at least one of Co, Mn and Al, and M2 includes at least one of Na, Ca, Nb, Ta, Mo, Zr, Ti, Cr, Cu, Zn, Sn, Ge, Ga, B, Mg, Ba, Si, Y, W, V and Sr.
12 . The cathode active material for a lithium secondary battery of claim 11 , wherein M1 in Chemical Formula 1-1 includes Co and Mn.
13 . A lithium secondary battery, comprising:
a cathode including the cathode active material for a lithium secondary battery of claim 1 ; and an anode facing the cathode.Join the waitlist — get patent alerts
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